In vehicles such as an automobile provided in recent years, in order to enhance the comfort level of occupants and prevent emission of noise to the outside of the vehicle, engine sound and other sound generated in association with a running condition of the vehicle have been reduced to the extent possible. With this configuration, however, there arises a problem in that the actual running condition such as vehicle speed and the sound audible to the occupant are less related to each other and, as a result, the driving feel of the automobile is deteriorated. Therefore, there has been developed a sound generating device for a vehicle, which is configured to generate the engine sound from a loudspeaker only toward the inside of a vehicle cabin without emitting the sound to the outside (see, for example, JP 2008-13064 A).
This sound generating device for a vehicle (driving sound transmitting device) includes a sound pressure sensor arranged inside an air inlet or an air intake pipe of an engine, a rotational pulse sensor for detecting an ignition pulse of the engine, an accelerator opening degree sensor for detecting a depressing amount of an accelerator pedal, a loudspeaker arranged inside an engine room or a vehicle cabin, for outputting driving sound of the engine, and a controller. The controller includes an order filter for changing a sound wave signal of the sound pressure sensor to be allowed to pass therethrough in accordance with an input frequency from the rotational pulse sensor, and a variable attenuator for increasing and decreasing a sound pressure of the sound wave signal passing through the order filter in accordance with an opening degree signal from the accelerator opening degree sensor. The sound wave signal output from the controller is amplified by an amplifier and output from the loudspeaker.